In this specification and claims, the term “sill” refers to the horizontal bottom part of a window or door as defined by ASTM E 2112-07 Standard Practice for Installation of Exterior Windows, Doors, and Skylights, section 3.2.121.
In this specification and claims, the term “pan flashing” or “sill pan flashing” refers to “a type of flashing used at the base of rough opening to divert incidental water to the exterior or to the exterior surface of concealed WRB (weather-resistive barrier),” as defined by ASTM E 2112-07 section 3.2.91. As further described in Note 3 to ASTM E 2112-07:                “sill pan flashing have upturned legs at the interior edge and ends of the rough opening to from a three-sided pan. They are intended to collect and drain water toward the exterior including water that may enter through the window unit (for example, between the jambs and sill) or around the window (between the rough opening and the fenestration). The pan flashing [or sill pan flashing] must be integrated with other flashings and the window assembly to capture water that may otherwise penetrate to the sill framing and allow it to freely drain to the exterior. The window, flashings, and pan are to be sealed in a manner that reliably inhibits air and moisture flow to the interior.”        
A “sill pan flashing” is different structurally and functionally from a “sill”. The sill is a structural part of a window or door assembly that connects bottom of the frame (jamb) members and does not extend to the full width of a rough opening, and does not collect or drain the water that enters around the door or window unit (between the jamb and the rough opening). A sill is not integrated with the Water Resistive Barrier (WRB).
FIG. 24 is a front perspective view provided in ASTM E 2112-07 as an illustration of the sill pan flashing.
It is desirable to provide a relatively low cost sill pan flashing for the entire rough opening to be installed underneath window and door sills for directional drainage of water and moisture which can be used for construction in all price ranges of housing, and for any door or window width. In one embodiment of the current invention, a base unit is provided which can be manufactured by extrusion and either cut to a desired length to fit the door or window width opening, or used with other similar elements and connectors to establish a desired final length. End pieces and optional center joining elements are provided for field assembly.
The prior art includes U.S. Pat. No. 5,921,038 to Burroughs which describes a window sill pan with an inclined plate and ribs perpendicular to the front edge. The patent includes a front cover, but does not disclose end members.
U.S. Pat. No. 6,385,925 B1 to Wark teaches an inclined plate with ribs perpendicular to the front edge. The Wark patent does not include a cover, but does have end members. Wark also describes the possible use of other window support means such as truncated cones. Wark describes the supports as being on the apparently solid inclined base.
It is desirable to provide a sill pan flashing that can be used for doors or windows of any length. It is desirable to provide an economical sill pan flashing that can be used in most construction. One way to provide a relatively low cost device is to extrude the base. It is desirable in such applications to provide window or door supports which can be extruded in relatively long lengths suitable to be cut in the field in order to accommodate different size windows and doors. It is desirable to extrude a unit which includes door or window supports in order to avoid attaching separate support elements to a base unit.
It is desirable to manufacture window and door sill pan flashing elements in an efficient and economical extrusion process, to supply the elements in relatively long lengths, and to cut the elements to a desired length at a construction site. This manufacturing and installation method may provide sill pan flashing units that are more readily available to builders and which are more economical that purchasing prefabricated sizes from a supplier who is required to stock a large number of possible widths. This manufacturing and installation method eliminates the need for special ordering of sill pan flashings for different field dimensions.
Also, if an injection molding tool were required for each size, then relatively high volumes of each size would be required to pay for the tool. It is difficult to order and store many different sizes of sill pan flashing for the variety of window and door dimensions which are used in construction. By designing the sill pan flashing for manufacture by extrusion, a single extrusion tool and a single injection molding tool for end pieces can provide sill pan flashing of a variety of lengths. In some embodiments, sections of base may be connected to establish a desired length. In other embodiments, the base may be cut to a desired length.